Abstract: The present invention provides a black water-based ink composition that has excellent resistance to light and ozone, has an excellent hue as a black ink, and also has excellent storage stability. A black water-based ink composition is prepared by combining at least one type of black dye selected from the group consisting of compounds expressed by the following formula (1) and salts thereof: and at least one type of dye other than a black dye, and the hue is adjusted by adding the dye other than a black dye. It is preferable if the dye other than the black dye is a compound that has at least one type of group selected from the group consisting of an —SO3H group, —COOH group, —SO3M group, and —COOM group (where M in these groups is an alkali metal atom), and is not an ammonium salt or a salt with an organic cation. It is also preferable for the dye other than the black dye to be a dye selected from the group consisting of yellow dyes and magenta dyes.

Abstract: To provide an ink set capable of recording images with good ozone fastness on a recording medium, an ink set of the present invention comprises at least a yellow ink composition, a magenta ink composition, and a cyan ink composition. The cyan ink composition contains at least one of the compounds expressed by formula (1) below as a cyan dye: and the magenta ink composition contains, as a colorant, at least one substance selected from the group consisting of compounds expressed by formula (2) below: and salts thereof (in formula (2), A represents an alkylene group, an alkylene group containing a phenylene group, or a group expressed by formula (3) below: and X represents a group selected from the group consisting of NH2, OH, and Cl).

Abstract: Objects of the present invention are to provide a magenta ink composition having good light-fastness and gas resistance, and excellent moisture resistance and clogging resistance, and to provide a magenta ink composition having excellent colorability in addition to these characteristics. The present invention provides a magenta ink composition containing, as colorants, at least one selected from compounds represented by undermentioned formula (1) and salts thereof, and at least one selected from compounds represented by undermentioned formula (2) and salts thereof. Moreover, the present invention also provides a magenta ink composition containing, as colorants, the above and in addition at least one selected from compounds represented by undermentioned formula (3). (Definitions of the symbols in the formulae are as in the claims.

Abstract: To provide a black aqueous ink composition for excellent light and gas fastness, an ink set including the ink composition, and an ink jet recording process using the same, the black aqueous ink composition contains at least a trisazo dye represented by Chemical Formula 31.

Abstract: The invention provides: an ink set comprising a yellow ink composition, a magenta ink composition, and a cyan ink composition, wherein the magenta ink composition contains as a colorant at least one member selected from compounds represented by the following formula (1) and salts thereof; and an ink set comprising two magenta ink compositions differing in color density, wherein the magenta ink composition having a lower color density contains as a colorant at least one member selected from compounds represented by the following formula (1) and salts thereof. Also disclosed are: an ink cartridge housing the ink set; a process for recording with the ink set; and recorded matter obtained by recording with the ink set.

Abstract: An ink composition and/or a recording medium are made to contain a compound expressed by general formula (1) and a hydrazide compound. An ink composition thereby obtained does not clog and the ink composition and recording medium thus obtained can offer high quality images that hardly cause yellowing of the resulting recording with superior light resistance. Recording and an inkjet recording method pertaining thereto are also provided.

Abstract: Disclosed is an ink composition which has good storage stability and, in addition, can yield prints having good waterfastness and lightfastness. The ink composition comprises an alkali-soluble colorant, a water-soluble organic solvent, water, and a cationic water-soluble resin comprising units (a) and units (b1) or units (b2): wherein R1, and R2, which may be the same or different, each represent a C1-5 alkyl group; R3 represents a hydrogen atom or a C1-5 alkyl group; and m and n are each 0, 1, or 2.

Abstract: The present invention provides an ink composition comprising at least water; at least one member selected from compounds represented by the following formula (1) and/or salts thereof; and at least one member selected from carboxyl group-containing aromatic compounds and/or salts thereof: 1

Abstract: Disclosed is an ink set comprising at least a normal yellow ink composition and a dark yellow ink composition, the lightness of the dark yellow ink composition being lower than that of the normal yellow ink composition. This ink set can realize recorded images having excellent color reproduction and image reproduction.

Abstract: The ink composition of the present invention contains a coloring agent, water, a water-soluble organic solvent which is a liquid at least at temperatures of 40° C. or less, and which has a solubility of 1 wt % or greater with respect to water at a temperature of 20° C., and a saturation vapor pressure of 1.7 Pa or less at a temperature of 20° C. (with said organic solvent being contained in the ink composition at the rate of 10 to 35 wt %), and one or more amidine type compounds. As a result, the present invention provides an ink composition, a recording medium, recorded matter and an ink jet recording method that make it possible to obtain images with a high image quality which are superior in terms of the gas resistance of the recorded matter.

Abstract: An ink composition and/or a recording medium are made to contain a compound expressed by general formula (1) and a hydrazide compound. An ink composition thereby obtained does not clog and the ink composition and recording medium thus obtained can offer high quality images that hardly cause yellowing of the resulting recording with superior light resistance. Recording and an inkjet recording method pertaining thereto are also provided.

Abstract: A composition, for ink jet recording, containing a cationic, water-soluble resin comprising a repeating unit represented by the following formula (I) can realize an image possessing excellent waterproofness and lightfastness and having no significant feathering or bleeding, especially no significant color-to-color bleeding: wherein R1 and R2 which may be the same or different represent a hydrogen atom or a C1-5 alkyl group, provided that R1 and R2 do not simultaneously represent a hydrogen atom; and n is 0, 1, or 2.

Abstract: The invention provides: an ink set comprising a yellow ink composition, a magenta ink composition, and a cyan ink composition, wherein the magenta ink composition contains as a colorant at least one member selected from compounds represented by the following formula (1) and salts thereof; and an ink set comprising two magenta ink compositions differing in color density, wherein the magenta ink composition having a lower color density contains as a colorant at least one member selected from compounds represented by the following formula (1) and salts thereof.

Abstract: To provide a black aqueous ink composition for excellent light and gas fastness, an ink set including the ink composition, and an ink jet recording process using the same, the black aqueous ink composition contains at least a trisazo dye represented by Chemical Formula 31.

Abstract: An ink composition and/or a recording medium are made to contain a compound expressed by general formula (1) and a hydrazide compound. An ink composition thereby obtained does not clog and the ink composition and recording medium thus obtained can offer high quality images that hardly cause yellowing of the resulting recording with superior light resistance. Recording and an inkjet recording method pertaining thereto are also provided.

Abstract: An aqueous ink comprising at least a colorant, a water-soluble organic solvent and a compound represented by general formula (I) shown below, wherein said water-soluble organic solvent stays liquid at a temperature of not higher than 40° C., exhibits a water solubility of not lower than 1% by weight at a temperature of 20° C. and a saturated vapor pressure of not higher than 1.7 Pa at a temperature of 20° C. and is contained in an amount of from 5 to 35% by weight: wherein Y represents a nonmetallic atom group required to form a 5- to 7-membered ring with C and N; X represents a hydrogen atom, oxyradical group, hydroxyl group, alkyl group, alkenyl group, alkinyl group, aryl group, acyl group, sulfonyl group, sulfinyl group, alkoxy group, aryloxy group or acyloxy group; and R1 to R4 may be the same or different and each represent a hydrogen atom or alkyl group, with the proviso that any two of R1 to R4 and Y may be connected to each other to form a 5- to 7-membered ring.

Abstract: The present invention provides an ink composition comprising at least: water; a cyan dye; and an aromatic compound having a carboxyl group and/or a salt thereof. Also disclosed are an inkjet recording method using the ink composition, and recorded matter recorded using the ink composition or by the inkjet recording method.

Abstract: A weight member is attached to a rotor so as to forcibly offset a center of gravity of a rotor from a rotating axis, centrifugal force moves two movable weight members to appropriate positions for canceling the unbalance due to the center of gravity offset from the rotating axis, and stoppers restrict the movement of the two movable weight members in a sectoral area opposite to the center of gravity so that the rotor is free from vibrations due to the characteristic angular velocity.

Abstract: A compound expressed by General Formula 1, whose weight reduction after 1 hour at 60° C. is no more than 1%, is contained in an ink composition and/or a recording medium. This makes it possible to provide an ink composition, a recording medium, printed matter, and an ink jet recording method with which the light resistance of the printed matter is excellent, there is no ink clogging, and a high-quality image with almost no yellowing of the printed matter can be obtained.

Abstract: Disclosed is an ink set comprising at least a normal yellow ink composition and a dark yellow ink composition, the lightness of the dark yellow ink composition being lower than that of the normal yellow ink composition. This ink set can realize recorded images having excellent color reproduction and image reproduction.